Tuesday, March 23, 2010

Nuclear "Waste"

Yucca Mountain is off the table and the blue ribbon panel meetings are starting to discuss long term solutions for waste storage. Will waste reprocessing be a viable option? Seems like a huge waste of potential energy to simply bury the spent fuel. On the other hand, the US has a lot of catching up to do to get into the waste reprocessing game.

Currently weapons grade fuel and reprocessed spent fuel is converted into mixed oxide (MOX) fuel for use in power reactors in several countries. The US has dedicated a significant amount of government research, but there is no current reprocessing or plans for future reprocessing.  There is a new facility in the works to convert weapons grade fuel into MOX fuel.  This is a new facility construction partnered by AREVA and Shaw Group.  http://www.moxproject.com/

History of reprocessing and associated technology

The main reason for reprocessing used fuel has been to recover unused uranium and plutonium in the used fuel elements completing the fuel cycle, gaining some 25% more energy from the original uranium in the process and thus contributing to energy security. A secondary reason is to reduce the volume of material to be disposed of as high-level waste to about one fifth. In addition, the level of radioactivity in the waste from reprocessing is much smaller and after about 100 years falls much more rapidly than in used fuel itself.

The recovery of all long-lived actinides together including plutonium can be then be used in fast reactors as they then end up as short-lived fission products. Long-term radioactivity is reduced in high-level wastes, and reducing the plutonium proliferation of the fuel cycle.

An Areva study (pdf) concludes that reprocessing and recycling would reduce U.S. waste volume by a factor of four for the same cooling period as once-through spent fuel -- about 50 years. Cooling period refers to the storage timer prior to internment in a long term waste storage site.  Such a cooling period allows radioactivity levels to be reduced to allow transport and storage.

Excellent article detailing the French process and state of US policy as of 2009:

I will add some additional technical data soon

No comments:

Post a Comment